1. Technical Field of the Invention
The present invention relates to an optical disc apparatus that uses an optical disc having tracks of lands and grooves as an information recording medium, and more particularly to technology for tracking pull-in during a seek or track jump.
2. Description of the Related Art
DVD-RAM, HD-DVD, and the like are currently available as optical discs having tracks of lands and grooves (hereinafter referred to as L/G structural tracks). When a tracking servo is applied to an optical disc of the L/G structural tracks during a recording or reproducing operation, the tracking servo is applied assuming that a light spot of a laser beam is in a groove position, PID information (address information showing physical characteristics of the optical disc) of a header part is read, and then discrimination between a land and a groove is made (hereinafter referred to as L/G discrimination) to determine the position of the light spot and detect a land/groove switching position (hereinafter referred to as an L/G switching position).
A conventional technology related to the present invention is disclosed in Japanese Unexamined Patent Publication No. Hei 11-316957. According to the patent publication, in an optical disc apparatus, to normally perform track-on (tracking pull-in) during a seek or track jump, a header part detecting circuit generates a header part detection signal from a tracking error signal, and outputs it to a tracking control circuit. The tracking control circuit performs track-on control in a data area other than a header area detected by the header part detection signal. Even when a header deviation due to the detection of the header part occurs, the instability of tracking pull-in is reduced to enable track-on.